Device for forming a flow restriction in a flow conductor

ABSTRACT

An hydraulically powered piston moves two curved dies toward each other to crimp a flow conductor positioned between the dies. Travel of the piston is limited to prevent complete crimping of the conductor and the structure holding the two dies for relative movement with respect to each other may be disassembled and reassembled for positioning about an axially extending flow conductor. The external curvature of the die surfaces is not substantially greater than the external curvature of the flow conductor to minimize cracking in the conductor as it is crimped. Locking means may be included in the crimping device to prevent the dies from separating from each other after the flow conductor has been crimped.

United States Patent 11 1 [111 3,751,964 owle 1451 Aug. 14, 1973 DEVICE FOR FORMING A FLOW 2,663,537 12/1953 Gagne 251/5 RESTRICTION IN A FLQW CONDUCTOR 2,890,855 6/1959 Little 251/5 [75] Inventor: Kermit G. Rowley, Houston, Tex. [73] Assignee: Tenneco Oil Company, Houston,

Tex.

[22] Filed: Sept. 21, 1970 [21] Appl. No.: 73,849

[52] US. Cl. 72/470 [51] int. Cl B2ld 17/00 [58] Field of Search 251/4, 5, 6, 7, 8, 251/9, 10, 112; l37/355.l6, 355.18; 81/300,

[56] References Cited UNITED STATES PATENTS 3,117,904 1/l964 Black 251/7 X 3,286,978 ll/l966 Lansky et al. 251/112 2,150,262 3/1939 Brittain 251/5 2,599,958 6/1952 Wallis 251/5 2,934,305 4/1960 Farris et al 251/5 Primary ExaminerMartin P. Schwadron Assistant Examiner-David R. Matthews Attorney-Eugene S. Coddou and Carlos A. Torres [5 7] ABSTRACT An hydraulically powered piston moves two curved dies toward each other to cri'mp a flow conductor positioned between the dies. Travel of the piston is limited to prevent complete crimping of the conductor and the structure holding the two dies for relative movement with respect to each other may be disassembled and re- 4 Claims, 3 Drawing Figures BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to means for forming flow constrictions in a fluid conduit. More specifically, the present invention relates to a device for forming a controlled restriction to flow in a conduit disposed in an oil or gas well structure.

US. Patent application Ser. No. 29,091 filed Apr. 16, 1970 now US. Pat. No. 3,647,006 and assigned to the applicant herein, discloses a method for stopping the uncontrolled flow of oil or gas from petroleum wells located in a body of water. In the described method, an access conduit line is hot tapped into the production tubing string through access windows formed in the well casing below the waters surface. In one form of the invention, the tubing is then partially crimped above the hot tap and solid particles are introduced into the production tubing through the access line where they are carried upwardly by the flowing well fluids to lodge within the crimped flow restriction and form a plug. The crimping mechanism of the present invention is designed to be employed as a crimping means in the foregoing method of stopping uncontrolled flow from an oil or gas well.

2. Brief Description of the Prior Art The prior art discloses a variety of devices which have been employed in well structures for the purpose of terminating flow through flow conduits in the structure. A large number of such devices called blowout preventers" include opposing rams which are driven toward each other to squeeze a flow conductor disposed between the rams completely shut. The prior art also includes devices of the opposed ram type which function to fully sever the flow conductor and drive resilient sealing means into contact to seal off flow through the severed conductor.

Ram-type devices such as the previously described blowout preventers are unsatisfactory for use in the formation of a crimp to be employed in the previously described well control method, since such devices do not function to provide a partial flow restriction but rather completely seal or completely sever the flow conductor. Complete crimping is undesirable in that the flow conductor is subject to rapid cutting caused by high pressure leakage flow past the crimped area. Moreover, the previously described method cannot be as efi'ectively employed where the well fluid escapes from the flow conductor in the vicinity of the restricted area. For this reason, devices of the type which sever the well conduit are also unacceptable for use in the method.

Another important requirement of the previously described well control method is that the crimping mechanism be capable of being quickly and easily assembled about the exposed flow conductor below the water surface. The majority of prior art crimping and sealing devices are generally of the type which must be installed during the construction of the well structure and are not well suited for application to an in-place flow conductor.

Even though conventional prior art devices might be otherwise suitable for use in forming a flow constriction without completely severing the flow conductor, such devices are generally objectionable in that cracks and breaks are produced in the flow conductor as it is squeezed closed. The formation of such cracks or breaks is to be avoided in the previously described method since high pressure fluid flow through the break may rapidly sever the flow conductor permitting the well effluent to escape and posing a substantial danger to personnel attempting to employ the steps of the method.

SUMMARY OF THE INVENTION The crimping device of the present invention includes a hydraulically powered piston which drives a connecting rod to move two opposed dies relatively toward each other to thereby form a flow restriction in a flow conductor extending between the dies. The con-' necting structure securing the dies for movement relative to each other may be quickly and easily disassembled so that the dies may be positioned on either side of an axially extending flow conductor, thus adapting the device for use with in-place well structures.

The opposed dies employed in the crimping device of the invention include a partially cylindrical outer surface which is specifically designed to deform the tubing conductor walls without inducing structural breaks in the conductor. The die curvature is also correlated to the curvature of the flow conductor being crimped, with the curves of each being substantially similar, to further prevent undesired cracking or stressing of the flow conductor.

Movement limiting structure is also included with the device to prevent full crimping of the flow conductor which prevents breakage. The supporting structure for the two opposed dies may be locked in crimped position, if desired, to prevent them from moving away from eachother to thereby maintain the restriction in the flow conductor until the desired fluid stoppage has been effected.

The foregoing features and advantages of the present invention as well as others will become more readily apparent from the following specification, the related drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical elevation, partially in section, illustrating the crimping device of the present invention in position about a well conduit;

FIG. 2 is an enlarged sectional view taken along the line 2-2 of FIG. 1; and

FIG. 3 is a partial sectional view taken along the line 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 of the drawings, the crimping device of the present invention has been indicated generally at 10. The device 10 is illustrated in position about a tubing string T which is positioned within a conventional well casing C. Where the invention is employed to control well flow in a structure set in a body of water, it will be understood that the casing C and tubing T extend upwardly to the well surface where they are equipped with conventional well head equipment. A supply line S extends between the device 10 and a source of hydraulic pressure, preferably located at the waters surface.

In accordance with the method for well control described previously, an initial step in terminating uncontrolled effluent flow through the tubing string T requires cutting a window C into the casing C at a point below the water surface and below the point of effluent escape from the tubing string T. Once access to the tubing string T is obtained in the manner illustrated in FIG. 1, the crimping device is positioned about the tubing string T and hydraulic pressure is supplied through the line S to form the desired partial restriction to flow in the tubing string. Once the flow restriction has been formed, uncontrolled well flow is terminated in the method more fully described in the previously referred to patent application.

FIG. 2 illustrates details in the construction of the crimping device 10. The device 10 includes a housing 11 within which is formed a compression chamber 12. A piston 13 is adapted to be moved axially through the chamber 12 under the influence of hydraulic pressure supplied from the supply line S. The line S is threadedly engaged with a removable base plate 14 which in turn is threadedly engaged within the housing 11. Wrench receiving lands 14a are provided at the base of the removable plate 14 to assist in assembling and disassembling the crimping device. An annular O-ring 15 is positioned between the plate 14 and the internal wall of the housing 11 to provide a leakproof seal at the base of the compression chamber 12.

An annular O-ring 16 is carried in a receiving groove formed along the external cylindrical walls of the piston 13 to effect and maintain a sliding seal between the piston and the internal walls of chamber 12. A piston rod 17 is threadedly engaged with the piston 13 and extends from a base 13a of the piston through the housing 11 to a first, movable, semi-cylindrical crimping die 18. The movable die 18 and connecting rod 17 are threadedly engaged in the manner illustrated in FIGS. 2 and 3 for simultaneous movement.

A connecting support structure extends from the housing 11 to a second, fixed, semi-cylindrical crimping die 19. The connecting structure includes two parallel plates 20 and 21 which are secured to the housing by means of screws 22 or other suitable means. The fixed crimping die 19 is secured to the plates 20 and 21 by means of screws 23 and by means of a cooperating slot and groove arrangement in the manner illustrated in FIG. 2

In operation, it will be understood that hydraulic pressure is introduced into the top of the chamber 12 through the connecting line S which causes the piston 13 to move from the plate 14 toward the base 120 of the chamber 12. Since the crimping die 19 is held stationary with respect to the housing 11, the movement of the piston 13 and connecting rod 17 effects a relative movement between the two crimping dies which decreases the spacing between the two dies in a crimping area indicated generally at A.

Referring jointly to FIGS. 2 and 3, it may be appreciated that the piston 13 is displaced by the hydraulic fluid until the piston base 130 engages the lower compression chamber surface 12a. When the piston has been thus moved to the bottom of its stroke, the tubing T is deformed in the shape of two opposed, semicylindrical depressions indicated in dotted line in FIG. 3. It should be noted that a restricted flow path continues to exist between the two indented portions created in the crimped tubing string T. By this means, undesired stress and back pressure are prevented from developing in the tubing string whereby the method of plugging the tubing string described in the previously referred to application may be effectively accomplished.

If desired, the dies 18 and 19 may be locked to prevent them from moving away from each other once the tubing T has been crimped by inserting bolts or other suitable means through bores 21 and 20' formed in the connecting structure and engaging the bolts in internally threaded bores 18 formed in the movable crimping die 18. Thereafter, if desired, the screws 22 may be removed and the rod 17 may be unthreaded from the die 18 so that the device 10 may be equipped with another connecting support and die assembly. This procedure may be required, for example, where the crimper 10 is to be employed with a plurality of tubing strings extending through the casing C.

It will be readily appreciated that before the device 10 is assembled about the tubing string T, the screws 23 and the crimping die 19 are removed to permit the supporting structures 21 and 20 to be positioned about the tubing string T and are thereafter repositioned in the manner illustrated in FIG. 2. Removal of the device 10 from about the tubing string T is effected by similarly disassembling the connecting structures 20 and 21 and the crimping die 19.

It should be noted that the external cylindrical surfaces 18a and 19a of the crimping dies 18 and 19, respectively, have a radius which approximates the radius of the tubing string T. It has been discovered that relatively small radius curvatures, in the neighborhood of the curvature of the tubing string and preferably having a diameter less than twice the diameter of the tubing string, are less likely to cause cracking and breakage of the tubing during the crimping operation. As best seen in FIG. 3, the device 10 is adapted to move the crimping die 18 along a line which intersects the geometric axial centers of the curved surfaces and 19a while simultaneously maintaining the curved surfaces parallel to each other. By this means, a uniform crimping action is effected to further ensure minimum stress and to reduce the likelihood of breakage.

From the foregoing, it may be appreciated that there has been disclosed a new and improved mechanism for uniformly imparting a physical deformation to a flow conduit without completely restricting flow through the conduit and without rupturing or unduly stressing the walls of the conduit. The provision for absolute limitation on the extent of crimping ensures the formation of a partial crimp.

It may also be appreciated that the device of the present invention is particularly well adapted to be assembled about an elongate flow conductor. In addition, the crimper of the present invention is lightweight thus assisting in its use below the waters surface by divers and other personnel who may be wearing restrictive clothing or protective gear.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials as well as in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

l. A crimping device for forming a restriction in a flow conductor comprising:

a. first and second die means;

b. support means supporting said first and second die means about a crimping area and permitting opposing movement of said die means, relative to each other;

c. access means included with said support means for permitting the placement of an elongate flow conductor within said crimping area between said first 5 and second die means;

d. powering means including piston and cylinder assemblies carried by said support means, said piston assembly being connected to at least one of said die means for moving said first and second die means toward each other for engaging and crimping said flow conductor to restrict the flow of fluid therethrough; and

e. said powering means being provided with limit means to arrest the movement of said piston assembly, limiting the movement of said die means toward each other by a predetermined amount to form a partial flow restriction in said flow conductor.

2. A crimping device as set forth in claim 1 in which said first and second die means are provided with convexly curved external surfaces adapted for crimping engagement with said flow conductor, the radius of curvature of said convexly curved external surfaces being less than approximately twice the radius of said flow conductor but not substantially less than the radius of said flow conductor.

3. A crimping device as set forth in claim ll further including locking means engageable with said piston assembly for preventing movement of said die means away from each other following the formation of said partial flow restriction in said flow conductor.

4. A crimping device as set forth in claim 3 further including separator means for separating said powering means from said die means following saidformation of said partial flow restriction. 

1. A crimping device for forming a restriction in a flow conductor comprising: a. first and second die means; b. support means supporting said first and second die means about a crimping area and permitting opposing movement of said die means, relative to each other; c. access means included with said support means for permitting the placement of an elongate flow conductor within said crimping area between said first and second die means; d. powering means including piston and cylinder assemblies carried by said support means, said piston assembly being connected to at least one of said die means for moving said first and second die means toward each other for engaging and crimping said flow conductor to restrict the flow of fluid therethrough; and e. said powering means being provided with limit means to arrest the movement of said piston assembly, limiting the movement of said die means toward each other by a predetermined amount to form a partial flow restriction in said flow conductor.
 2. A crimping device as set forth in claim 1 in which said first and second die means are provided with convexly curved external surfaces adapted for crimping engagement with said flow conductor, the radius of curvature of said convexly curved external surfaces being less than approximately twice the radius of said flow conductor but not substantially less than the raDius of said flow conductor.
 3. A crimping device as set forth in claim 1 further including locking means engageable with said piston assembly for preventing movement of said die means away from each other following the formation of said partial flow restriction in said flow conductor.
 4. A crimping device as set forth in claim 3 further including separator means for separating said powering means from said die means following said formation of said partial flow restriction. 